Kenneth L King

US Patent:

55504345, Aug 27, 1996

Filed:

May 23, 1994

Appl. No.:

8/247832

Inventors:

Kenneth J. King - Palatine IL
Robert M. Zawislak - Palatine IL
Richard C. Vokoun - Palatine IL

Assignee:

Northrop Corporation - Los Angeles CA

International Classification:

H05B 3702

US Classification:

315160

Abstract:

Electrical activation of an arc lamp is accomplished by a plurality of circuits, each of which has a boost topology including a capacitor and a charging circuit for charging the capacitor by a series of current pulses. One of the circuits is an igniter circuit and includes a transformer to convert voltage from a relatively low voltage supply to a relatively high voltage for striking an arc within the lamp. A second of the circuits provides for a steady flow of current to maintain the arc after completion of ignition of the arc. The second circuit is protected from the high voltage of the first circuit by a saturable reactor connected in series between the second circuit and the arc lamp. A further circuit, employed as boost modulator, and constructed with the same form of boost topology, may be connected via a diode to a junction between the saturable reactor and the second of the foregoing circuits, the third circuit being useful for providing substantially larger amounts of plasma current, when desired, than such plasma current as can be provided by the second circuit. Also, if desired, the second circuit can include means for varying amplitudes of charging current pulses in response to an external signal, such as an audio signal, thereby to allow for communication of data on a beam of radiation emitted by the arc lamp.

US Patent:

56916078, Nov 25, 1997

Filed:

Apr 26, 1996

Appl. No.:

8/638458

Inventors:

Robert Matthew Zawislak - Palatine IL
Kenneth John King - Algonquin IL
John Michael Rein - Elgin IL
Jeffrey Coe Perkins - Island Lake IL

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

G05F 100

US Classification:

315308

Abstract:

A single-stage modular modulator for pulsed illumination sources uses a full-range converter which converts unregulated DC to a 40-50 kHz carrier modulated at a frequency of a few hundred to a few thousand hertz. The modulated carrier is applied to the illumination source through a step-down transformer followed by a low-pass filter circuit which removes the carrier. The converter is controlled by a modulation control which uses an instantaneous load current signal feedback to follow a modulation commend signal, and a current mode signal representing the primary current of the transformer to compensate for converter output variations caused by input voltage variations.